Hard to pinpoint exactly, but sometime in the mid 70's. My grandfather and all my uncles were obsessed with wrestling. Being the youngest (smallest), I always got a spot right in front of the big box television on the floor.
Also, there were always wrestling magazines around. Pretty sure I learned to read with wrestling magazines. To the horror of my elementary school teachers, I used to always bring them with me to school. Back then, the covers always featured wrestlers wearing a crimson mask.